ARCHAEOPTERYX - THE MISSING LINK
An artist's representation of Archaeopteryx
Archaeopteryx was possibly the most controversial prehistoric remain ever dug up, it is the oldest known bird fossil, and most biologists accept it as conclusive proof that dinosaurs evolved into birds. Archaeopteryx had three toes armed with claws and long, strong legs. Clearly it walked and perched like a bird. Its head had the reptilian feature of jaw bones. Its spine was extended into a bony tail - just like a reptile's. On both sides of the tail bones, clearly visible, were the clinching characteristics of birds - feathers. All experts agree that while it has some unusual features it was a true bird and was able to fly, even if not very strongly. It had air-filled bones like birds we find today and asymmetrical flight feathers. The brain structure is similar to that of modern birds. A study of endocasts of an Archaeopteryx skull concluded, among other things, that it had an enlarged forebrain with neurological and structural adaptations and enhanced somatosensory integration required for a lifestyle involving flying ability. Archaeopteryx's feathers and birdlike wishbone — along with reptilian features such as a long bony tail, claws and teeth — are seen as strong evidence that birds evolved from dinosaurs.